Radiological Society of North America/Quantitative Imaging Biomarker Alliance Shear Wave Speed Bias Quantification in Elastic and Viscoelastic Phantoms.

Objectives: To quantify the bias of shear wave speed (SWS) measurements between different commercial ultrasonic shear elasticity systems and a magnetic resonance elastography (MRE) system in elastic and viscoelastic phantoms.

Methods: Two elastic phantoms, representing healthy through fibrotic liver, were measured with 5 different ultrasound platforms, and 3 viscoelastic phantoms, representing healthy through fibrotic liver tissue, were measured with 12 different ultrasound platforms. Measurements were performed with different systems at different sites, at 3 focal depths, and with different appraisers.

Artifacts in Sonography - Part 3.

As a continuation of parts 1 1 and 2 2, this article discusses artifacts as caused by insufficient temporal resolution, artifacts in color and spectral Doppler sonography, and information regarding artifacts in sonography with contrast agents. There are artifacts that occur in B-mode sonography as well as in Doppler imaging methods and sonography with contrast agents, such as slice thickness artifacts and bow artifacts, shadows, mirroring, and artifacts due to refraction that appear, for example, as double images, because they are based on the same formation mechanisms. In addition, there are artifacts specific to Doppler sonography, such as the twinkling artifact, and method-based motion artifacts, such as aliasing, the ureteric jet, and due to tissue vibration.

Biphasic transdermal iontophoretic drug delivery platform.

Transdermal iontophoresis is an active drug delivery method that has the potential to transform treatment of conditions such as acute pain that require a succession of on-demand metered-dose drug deliveries. However, current monophasic iontophoresis methods fail to meet these requirements due to their inability to halt the passive diffusion of active agents when therapy is not required. We have developed a biphasic iontophoretic system to overcome these limitations.

Sound speed correction in ultrasound imaging.

A constant sound speed of 1.54 mm/micros is generally used by ultrasound imaging systems for delay and timing. However, the body's sound speed in-homogeneity can lead to defocusing and increased clutter.